The Australian Government has begun transferring asylum seekers to Papua New Guinea - including women and children as young as 10 - but concedes there have been too many boat arrivals in the past few months to process all refugee claims offshore.

As a result, Immigration Minister Chris Bowen says asylum seekers will be released into the community on bridging visas, even if they arrived after the Government reintroduced offshore processing and put in place the so-called no-advantage test.

Too many arrivals

Speaking at the same time as Mr Bowen's media conference, Opposition Leader Tony Abbott continued the Coalition's attack on Labor's border protection policies.

"The Government today is boasting that some 18 people have been sent to Manus Island," Mr Abbott told reporters in Perth.

"What about the 30,000-plus illegal boat arrivals who have come to this great big island since this Government changed the policy that's working.

"It's just not good enough that this Government thinks it's an achievement to send just 18 people to Manus, when you've got 2,000 people coming every month."

More than 7,500 asylum seekers have arrived by boat since mid-August when the Government announced it would reopen the detention centres on Manus Island and Nauru.

That is despite warnings from the Government that anyone who arrived after that date risked being sent to one of the offshore centres to have their refugee claims processed.

Mr Bowen has today conceded there have been too many arrivals since August to send all asylum seekers to either Manus Island or Nauru, and some people will have to be released into the community.

"Transfers to Nauru and Manus Island will continue, however in the coming weeks and months my department will begin releasing some people who arrived by boat on or after August 13 into the community on bridging visas," he said in a statement.

"Consistent with no advantage, people from this cohort going onto bridging visas will have no work rights and will receive only basic accommodation assistance and limited financial support."

Opposition immigration spokesman Scott Morrison is warning that the continued use of bridging visas is likely to tempt more asylum seekers to try to reach Australia by boat, because it allows people to spend only a short period of time in detention before being released into the community.

He says more than 16,000 people have arrived on boats since the Government began a large-scale use of the visas last year.

"This Government has become completely overwhelmed by the problem of their own creation," Mr Morrison told reporters in Sydney.

"The Government's announcement today - that they will be reopening another 600 onshore detention beds, plus opening thousands more places for community release - is an open admission by this Government that they cannot stop the boats."

The Greens have lashed out at Mr Bowen's announcement, describing the policies as "more extreme" than those introduced by the former Howard government.

The party's immigration spokeswoman, Senator Sarah Hanson-Young, has likened the bridging visas to the temporary protection visas demanded by the Coalition.

"We've now got John Howard's Pacific solution, we now have John Howard's temporary protection visas," Senator Hanson-Young said.

"The question to the Government is when are they going to look at how failed those policies were then, how failed those policies are now, and change tack?"

Greens leader Christine Milne says it is clear Labor's policies have failed to stop the boats, arguing that "deterrence does not work".

"Just becoming crueller and crueller and crueller is not going to change the fact that you can never be as cruel as the circumstances from which people are running," she said.

Mr Bowen says the Government will reopen the Pontville detention centre in Tasmania and also expand the capacity at the Melbourne Immigration Transit Accommodation by about 300 places.

"Recent high arrival rates have placed pressure on our detention network, and it's sensible in managing this and also in terms of prudent contingency planning, that we take some steps to expand the capacity of our onshore detention network," he said.

Returned home

The Government has also revealed that yesterday an Afghan man was involuntarily returned home after his claims for refugee status were rejected.

It is the first time someone has been sent back to Afghanistan under an agreement signed between that country's government, Australia and the United Nations refugee agency last year.

Separately to that, a group of 100 Sri Lankans are being involuntarily flown back to Colombo on an Air Force plane - the ninth such removal this month.

"We'll continue these returns for as long as it takes for people who might be tempted by the wiles of people smugglers in Sri Lanka to undertake economic migration to realise that that path of migration to Australia is closed," Mr Bowen said.

"Our humanitarian program is for people who are at risk of persecution, not for people seeking to undertake economic migration."

The Government has faced stinging criticism from Amnesty International in relation to the living conditions within the detention centre on Nauru, with the group describing them as "completely unacceptable" and expressing concern about the mental health of detainees.

We'll continue these returns for as long as it takes for people who might be tempted by the wiles of people smugglers in Sri Lanka to undertake economic migration to realise that that path of migration to Australia is closed.

Immigration Minister Chris Bowen

Mr Bowen says he is not surprised that Amnesty International has spoken out against offshore processing, but he has defended the way the facility is being run.

"We provide all the necessary care and support to people in a difficult situation," he said.

"But as I've said to you, hundreds (or) thousands of people have died by boat getting to Australia.

"There is a moral obligation to do something about that - that is what we're doing."

One of the issues that particularly concerns Amnesty International is the indeterminate timeframe being imposed on asylum seekers held on the island.

Mr Bowen today revealed that initial interviews with asylum seekers would begin next week, with full assessment of refugee claims beginning next year.

"Of course, the issuing of protection visas will not be considered for a substantial amount of time."

"The no-advantage test will mean that people will wait for a very substantial period - could it be five years? Yes it could."

The Government has now signed a contract with Brisbane-based construction firm Canstruct to begin building the first phase of the permanent detention centre on Nauru which will house 900 asylum seekers.

"A large number of the construction staff are expected to be locally-engaged Nauruans," Mr Bowen said.

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